1. Field of the Invention
The present invention relates to a system for diagnosing a failure that occurs in an engine component.
2. Description of the Related Art
A conventional type of such engine failure diagnosis system is disclosed in JP-Y-Hei 5-11331 and JP-A-2001-193542. More specifically, in JP-Y-Hei 5-11331, an engine failure diagnosis system is activated by inserting a spare fuse into a terminal to energize circuits for sensors and electric components of the engine. The engine failure diagnosis system is designed to diagnose a failure that has occurred in the sensors or electric components, and indicates the diagnosis result by turning an alarm lamp ON.
In JP-A-2001-193542, an engine failure diagnosis system is designed to use a PC. The PC is connected to an engine control unit (ECU). Sensors provide the ECU with operating condition data concerning engine components which are driven while the engine is running. The engine failure diagnosis system obtains the operating condition data and displays the data on a screen of the PC.
However, the system described in JP-Y-Hei 5-11331 is designed to perform failure diagnosis by checking an electrical condition, such as energization. This allows the failure diagnosis of a member to be energized when in use, such as a sensor and an electric component. In contrast, the failure diagnosis is difficult to perform for the engine components that are driven while the engine is running, such as an injector, a fuel pump, and a valve. Especially, the failure diagnosis is difficult to perform at the time when the engine is stopped.
The system described in JP-A-2001-193542 is designed to display the operating condition data on the PC screen in order to provide information to estimate a location where a failure has occurred in the engine components. However, the operating condition data can be only obtained while the engine is running, and thus this system is only usable while the engine is running. In addition, the systems described in JP-A-2001-193542 and JP-A-2001-123918 are carried out by at least connecting the PC to the ECU. It is thus time consuming to start failure diagnosis. At the same time, these systems cannot be used in locations where a PC is not available for use, which imposes a constraint on the possible repair environments.